Writing Text on a map

Hello,
Please, I am finding it so difficult to Write on my map and the gmt documention is too technical understand below is the command I used. An example of text I Intend to Write on the map is “GeoB18530-1” which is a core name

#!/usr/bin/env bash
gmt begin image
    gmt coast -R-100/-10/35/80 -Jl-55/15/30/80/1:50000000 -Wthin -S -Wthin -B -N1/thick,red 
    gmt makecpt -Cetopo1 -T-5000/1000/1
    gmt grdimage @earth_relief_10m -I -C -B
    echo 49W 42E | gmt plot -BWSen -Sa0.3c -Gred -N -Wp1
    echo 49W 42E | gmt text GeoB18530-1 -R-49/42  -Bb -F+aO -Gblack -N
    gmt colorbar -DJBC -B1000
gmt end show 

Thank you.